Strap apparatus for stacked articles

ABSTRACT

A method and apparatus for banding a stack of planar articles, including a blank that has an initial length that is less than the circumference of the stack to be banded and a width that is greater than the height of the stack to be banded, wherein the band is a monolithically formed band without seams that is created through advantageous slitting and folding of the blank.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention is directed to strapping apparatus and methods for stacked articles, in particular articles that are stacked and packaged, without a discrete surrounding container.

[0003] 2. Prior Art

[0004] Many articles that are shipped are not contained in separate discrete containers. In particular, many articles, such as ceiling tiles are simply stacked, with possibly a thin sheet of material separating the bottom layer of articles from the upper surface that the stack is resting on. The entire stack may be banded or strapped. Thereafter, the entire assembly of stacked articles and the pallet, may be wrapped in shrink-wrap plastic material.

[0005] Some sort of strapping or banding is usually preferred, so that the individual articles, being generally flat articles, of one layer will not slide relative to layers above or below. However, relatively narrow metal or plastic straps may be undesirable, in that damage to the stacked articles, in the form of cracking or scratching or other similar damage may occur. Accordingly, banding that is wide, so as not to present sharply defined load-bearing edges, is needed.

[0006] Prior art paper banding or strapping apparatus are known. Such paper banding is typically in the form of a circumferential band, usually formed from paperboard material, such as clay coated news back (a recycled newspaper-based material). The strap is typically as wide as the stack is high. Stacks, such as of ceiling tiles, are usually in standardized footprints of two feet by two feet (nominal), or two feet by four feet (nominal). As is well know by those skilled in the art, the actually dimensions of such stacks are actually slightly smaller than the nominal dimensions. In the larger size stack, a band having a final circumference of at least 144 inches (nominal) will require a length of several inches in excess of that amount, to permit sufficient overlap for creating the seam. Because standard paper die-cutting machines are not capable of handling strips of such material of that length (indeed, a length of about 110 inches is the typical maximum length that such apparatus can cut), a band for surrounding such a stack must be formed from two, separate, lengths, so that the resulting surrounding band will have two transverse seams. Seams, in general, can create issues with respect to the strength of the resulting banded package, as well as in adding additional steps in the formation of the stack, and in excess use of material.

[0007] It would be desirable to provide a method and apparatus for banding a stack of articles, such as substantially planar articles, that are capable of providing a band of paper material for oversize stacked articles.

[0008] It would also be desirable to provide a method and apparatus for banding a stack of articles, in which the band is provided with a minimum number of seams or manufacturer's joints.

[0009] It would also be desirable to provide a method and apparatus for banding a stack of articles, which results in a reduction in the amount of paper material that is required.

[0010] These and other desirable characteristics of the invention will become apparent in light of the present specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a plan view of a blank for forming a circumferential strap, according to a preferred embodiment of the invention.

[0012]FIG. 2 is a perspective view of a blank according to FIG. 1, positioned above a stack to be wrapped.

[0013]FIG. 3 is a perspective view of the blank according to FIG. 1, formed into a circumferential strap.

[0014]FIG. 4 is a perspective view of an alternative embodiment of the invention, wherein the circumferential strap is formed from a single blank that is split into two separate pieces, prior to scoring, placement around a stack, and rejoining.

DETAILED DESCRIPTION OF THE DRAWINGS

[0015] While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will be described herein in detail, a specific embodiment, with the understanding that the present invention is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

[0016]FIG. 1 is a plan view of a blank for forming a circumferential strap, according to a preferred embodiment of the invention. Any numerical values that are given are provided simply by way of example of a preferred embodiment of the invention, and are not intended to limit the invention to the values given. Blank 10 is a single, monolithically formed piece of sheet material. In a preferred embodiment of the invention, blank 10 is formed from 28 point clay coated news back (paper based on recycled newsprint having a nominal thickness of 0.028 inches), although other similar materials and dimensions may be used, depending upon the performance requirements of the particular application. Unless otherwise specified, in the illustration of the blank 10, the usual conventions of those skilled in the art of fabrication of paper products are followed, in that solid lines within the interior of the blank denote complete through-cuts or apertures, and broken lines within the interior of the blank denote lines of weakness, such as scores, fold lines or perforations, for the purposes of facilitate folding of that portion of the blank.

[0017] Blank 10 has an internal longitudinal die cut, extending from point 12 to point 14. Blank 10 includes lines of weakness 16, 18, 20, 22, which may be fold lines, score lines or interrupted perforations, so long as the tensile strength of blank 10 is not appreciably compromised.

[0018] Blank 10 also includes lines of weakness groups 24, 26, 28 and 30. In one preferred embodiment, each group of lines of weakness includes three spaced lines, as illustrated. In alternative embodiments, each group of lines of weakness may have as few as two lines, up to as many as ten lines. The spacing between adjacent lines of weakness in each group may range from approximately one-sixteenth of an inch, up to as much as one-half inch.

[0019] Blank 10 further comprises elongated length panels 32, 34; width panels 36, 38, 40 and 42; and hinge panels 44 and 46.

[0020]FIG. 2 is a perspective view of a blank 10 according to FIG. 1, positioned above a stack 15 to be wrapped. FIG. 2 demonstrates how unarticulated blank 10 will be longer and possibly narrower than a stack 15, which is to be wrapped. Preferably, for a given stack height H, the width of blank 10 will be approximately twice H (two times H). Further, for a given stack length L, length panels will each have a length slightly greater than L. Further for a given stack width W, width panels 36 and 40 each have a length approximately {fraction (1/2)} W, whereas width panels 38 and 42 each have a length substantially in excess of ½ W,

[0021]FIG. 3 is a perspective view of the blank according to FIG. 1, formed into a circumferential strap. Formation of the strap is accomplished by folding blank 10 lengthwise about lines of weakness 16 and 18. By pushing hinge panels 44 and 46 toward one another, blank 10 assumes the configuration shown in FIG. 3. As shown in FIG. 3, the portions of width panels 38 and 42 that are adjacent fold lines 16 and 18, tend to only slightly deflect (possibly as little as 15 degrees) out of plane from their respective remaining portions of panels 38 and 42, so that hinge panels 44 and 46 are folded back toward their respective adjacent width panels 36 and 40, with an included angle of considerably less than 90 degrees, perhaps as little as 15 degrees.

[0022] While formation of an unfolded blank into a formed band may be performed by hand, in a preferred embodiment of the invention, such formation will be performed by automated machinery. Such automated machinery (not shown) may be readily constructed or adapted from known machinery, by those of ordinary skill in the art of making machinery for banding stacked articles, having the present disclosure before them. By providing multiple lines of weakness in each group 24, 26, 28, 30, even if there is some slight difference in placement of the unfolded blanks into such a formation machine over successive ones of the stacks of articles being banded, the unfolded blanks will simply fold along whichever lines of weakness in each of groups 24, 26, 28, 30 are most closely positioned to the respective “corner” areas being defined by folding guides of the formation machine.

[0023] The band is then slipped around a stack of articles (again, manually or preferably, in an automated manner), and affixed in place by any suitable means, such as surrounding the entire stack with plastic shrink-wrap material. Because the deflected ends of width panels 38 and 42, and their respective adjoining hinge panels 44 and 46, respectively, do not stick out from the sides of the width ends of the stack, upon application of the shrink wrap, the deflected portions of panels 38 and 42 are readily pushed back toward a position substantially flush with the remaining portions of those panels, and hinge panels 44 and 46 are folded completely back upon width panels 36 and 40.

[0024]FIG. 4 is a perspective view of an alternative embodiment of the invention, wherein the circumferential strap is formed from a single blank that is split into two separate pieces, prior to scoring, placement around a stack, and rejoining. The steps in the process are shown from right to left. The stack to be wrapped has been omitted for clarity of the illustration. Likewise the machinery for effectuating the steps shown have been omitted, as not being necessary for a complete understanding of the operation of the invention.

[0025] In the first step A of the alternative embodiment, the strap material (roll stock) is double the width of the height of the stack to be wrapped. The roll stock 100 is cut into the required length, which accommodates the total of one side and one end of the stack to be wrapped, plus a desired amount for permitting overlapping of the ends of the pieces of the roll stock, after splitting.

[0026] In the next step B, the roll stock is cut down the middle into two identical strips 102. In step C, the pieces are turned from horizontal to vertical, and two sets of (preferably) three parallel scores 104 are placed in each strip 102. As the strips are brought alongside a stack to be wrapped (not shown), step D, first the ends 108 of one of the strips 102 are folded (such as by paddles, not shown) perpendicular to the stack, so that the ends 108 are alongside the ends of the stack. Then the ends 108 of the other of the strips 102 are folded, perpendicular, to overlie the first-folded ends, and affixed in place, such as by any suitable adhesive, resulting in a fully formed strap 110, around a stack, step E.

[0027] After strapping, the stack with wrap, can be shrink-wrapped or otherwise suitably packaged (not shown).

[0028] The foregoing description and drawings merely explain and illustrate the invention, and the invention is not so limited as those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention. 

1. A strap apparatus, for wrapping a stack of planar articles, wherein the stack has a length, width and height, and a top, a bottom, and four peripheral faces defining a perimeter, for wrapping the stack around the perimeter of the stack, the strap apparatus comprising: first and second strips, formed from a single length of strap material having a width substantially equal to twice the height of the stack to be wrapped, and a length greater than one-half the length of the perimeter of the stack, such that each strip has a width substantially equal to the height of the stack to be wrapped and a length greater than one-half the length of the perimeter of the stack; each of the first and second strips having a first end and second end; each of the first and second strips having formed thereon two regions of reduced resistance to bending, disposed a corresponding to corner regions of the stack to be wrapped; the first and second strips being connected at their respective first and second ends, when the strap apparatus is in position around the stack to be wrapped.
 2. The strap apparatus according to claim 1, wherein the first and second strips are not completely separated from one another during formation from the length of strap material, so that the respective first ends and second ends of the first and second strips are monolithically formed together with one another, and not separated when the strap apparatus is placed on the stack to be wrapped.
 3. The strap apparatus according to claim 1, wherein the first and second strips are completely separated from one another, when the first and second strips are formed from the length of strap material.
 4. The strap apparatus according to claim 1, wherein each region of reduced resistance to bending comprises at least one score line extending from one lateral edge of one of the first and second strips to another lateral edge of said one of the first and second strips.
 5. The strap apparatus according to claim 4, wherein the at least one score line comprises at least two parallel score lines.
 6. The strap apparatus according to claim 5, wherein the at least two parallel score lines comprises three parallel, spaced apart score lines. 